Device for catalytically dissolving hydrogen peroxide

ABSTRACT

An apparatus for the catalytic decomposition of H 2 O 2  in an aqueous solution which is a contact lens care agent, wherein the catalyst is formed by a shaped body which is roughened by sand blasting and which is coated by a platinum layer  1  which is produced by sputtering.

The invention concerns an apparatus as set forth in the classifyingportion of claim 1.

In an apparatus of that kind which is known from U.S. Pat. No.5,275,784, it is known, for contact lens care, for catalytically activeplatinum metal to be deposited in the form of a layer, for example bysputtering, on a support of polymer material, for the purposes ofhydrogen peroxide decomposition, in an aqueous care solution.Difficulties are encountered here in regard to adequate adhesion betweenthe catalytically active platinum layer and the plastic support.Relatively large amounts of platinum are required for the deposit of thecatalytic platinum layer.

It is known from German patent specification DE 24 25 714 B2 for contactlenses and in particular soft contact lenses to be sterilised by meansof hydrogen peroxide in an aqueous, in particular 3% aqueous hydrogenperoxide solution. To remove residues of hydrogen peroxide, they aredecomposed by means of a decomposition catalyst to water and oxygen.That decomposition operation can also be conducted in the treatment bathfor the contact lens sterilisation and disinfecting treatment.

The catalyst has a catalytically inactive carrier material on which acatalytically active layer is disposed. In the known catalyst that layeris formed from electrolytically deposited platinum black.

It is also known from U.S. Pat. No. 5,306,352, after the sterilisationof contact lenses by means of hydrogen peroxide, for residues of thehydrogen peroxide to be decomposed by means of a suitable catalyst, thecatalyst material being applied to a carrier or substrate of plasticmaterial.

The object of the invention is to provide an apparatus of the kind setforth in the opening part of this specification with which improvedadhesion between the platinum layer and supports is achieved.

In accordance with the invention that object is attained by thecharacterising portion of claim 1.

The platinum layer can be applied in the form of an extremely thin filmto the preferably roughened surface of the shaped body of glass or theTiO_(x)N_(y)-support, the film preferably imitating the surfaceroughness. That not only provides for improved adhesion between thecatalytically active platinum film and the support, but in addition areduced amount of platinum metal is required in the layer-formationprocedure. A sufficiently large catalytically active surface layer isproduced on the shaped body with a small volume in respect of the shapedbody or a reduced surface area in terms of the shaped body. A preferredthickness for the platinum layer is in the range of from 0.1 to 1 g/m².

The surface roughness is preferably produced by mechanical surfacetreatment, in particular by particle blasting. Preferably the blastingprocess is a sand blasting process for use in roughening the surface ofthe support. The shaped body can comprise a suitable material.Preferably however glass is used as the material for the shaped body. Ithas been found that a glass surface which is roughened by sand blastingaffords excellent adhesion in relation to the platinum layer, inparticular when it is applied by sputtering. An extremely thin layer canbe produced by sputtering on the glass surface which is roughened bysand blasting.

That platinum layer which is produced by sputtering is obtained by aplatinum target being bombarded with high-energy ions of an inertsubstance, for example argon, neon and the like, so that platinum isdeposited in pure form as a platinum layer on the shaped body. Theshaped body provided with TiO_(x)N_(y) can comprise plastic material oranother suitable carrier material such as ceramic and the like. Theplatinum layer which is deposited by sputtering has a high level ofadhesion on the shaped body which is roughened in particular by sandblasting and can be formed as a thin film of uniform thickness. Theuniform thin layer with a high degree of purity can be appliedreproducibly in terms of its thickness in a controlled manner bysuitable process control in the sputtering operation. In particular thesize of the platinum layer may be such that it can be used upon use ofthe catalyst in an aqueous, in particular 3% hydrogen peroxide caresystem for contact lenses. The layer may be of such a nature that asufficient sterilisation effect is achieved by the hydrogen peroxide onthe contact lenses to be treated, in particular soft contact lenses,with subsequent decomposition of any residual hydrogen peroxide stillpresent in the treatment solution.

The catalytically active apparatus may preferably be a component of acontact lens care system in which the contact lens is disposed in acontainer and the contact lens care and sterilisation procedure iseffected in that container by means of aqueous care agent solution witha 3% hydrogen peroxide content. The platinum layer is adjusted in such away that the hydrogen peroxide has a sufficient period of action fordisinfecting the contact lenses to be treated in the container and thatsubsequently to the disinfecting treatment residual hydrogen peroxide iseffectively broken down into the constituents water and oxygen.

The invention will be described in greater detail by means ofembodiments with reference to the Figures in which:

FIG. 1 shows a first embodiment,

FIG. 2 shows a second embodiment, and

FIG. 3 diagrammatically shows a part of the catalytically active surfacein the two embodiments.

The embodiments illustrated in FIGS. 1 and 2 are used in contact lenscare and each have a container 4 which can be used as a storage or carecontainer for contact lenses. The contact lenses to be treated aredisposed in a basket 9 which can be pivoted open, as is known forexample from U.S. Pat. No. 5,275,784. In the care procedure the contactlenses to be treated are immersed in the container 4 in an aqueous careagent solution which has a 3% hydrogen peroxide content. The basket 9can be fixed to a cover 10 which can be screwed on to the container 4.

To close the bottom the embodiment of FIG. 1 has a bottom portion 3which can be screwed by means of screwthread engagement 5 to the lowerportion of the container 4. The embodiment shown in FIG. 2 also has acontainer bottom 7 which can be screwed on.

In the embodiment shown in FIG. 1 the container bottom or the screw-onbottom portion 3 preferably comprises glass. The bottom portion 3 formsthe shaped body or the support for a catalytically active platinum layer1 applied to the inside of the bottom portion 3. The surface which iscovered with the platinum layer 1 has been previously roughened by amechanical treatment process, in particular a blasting process, in whichthe surface was treated with particle blasting jets, in particular sandblasting jets, thus giving a roughened surface 2 on the glass materialof the bottom portion 3. The configuration of the roughened surface 2 onthe glass support (bottom portion 3) and the platinum layer appliedthereto is diagrammatically shown in FIG. 3. As can be seen from FIG. 3the platinum layer 1 which was preferably applied by sputtering adaptsitself to the roughnesses of the surface and in relation to the glasssupport enjoys an elevated level of adhesion by virtue of the roughnessof the surface which was preferably produced by a sand blastingtreatment. In the embodiment of FIG. 1 substantially the entire bottomregion, that is to say the inside surface of the bottom portion 3, isroughened and covered with the catalytically active platinum layer.

In the embodiment shown in FIG. 2 the screw-on container bottom 7 cancomprise the same plastic material as the container 4. Provided on thecontainer bottom 7 is an insert 6 in the form of a glass plate which isapertured or which has bores 8. The glass plate is preferably roughenedat its underside as shown in FIG. 3 and provided with the platinum layer1. It is however also possible for the top side to be roughened andprovided with the platinum layer 1. The platinum layer is also appliedin the same manner by sputtering in this embodiment. The underside ofthe apertured glass plate of the insert 6 is held at a given spacingfrom the container bottom 7 by spacers 11. That ensures that the oxygenproduced upon catalytic decomposition rises in the form of oxygenbubbles and thus causes a circulatory effect so that hydrogen peroxideto be decomposed is circulated (arrow 12) and effectively decomposed.Lateral spacers 13 may also be provided in order to promote thecirculatory effect.

What is claimed is:
 1. Apparatus for catalytic decomposition of hydrogenperoxide in an aqueous solution, comprising a receiving containercontaining the aqueous solution, and a shaped body coated with aplatinum layer acting as a catalyst and having a surface area which isin a direct contact with the hydrogen-peroxide containing aqueoussolution, wherein the platinum layer is applied by sputtering on theshaped body which is comprised of glass, and wherein the platinum layerhas a thickness in a range of from 0.1 to 1 g/m².
 2. Apparatus accordingto claim 1 wherein the shaped body is roughened by mechanical surfacetreatment.
 3. Apparatus according to claim 2, wherein the treatment isone of particle blasting and sand blasting.
 4. Apparatus according toclaim 1, wherein the platinum layer is applied to a roughened surface ofthe shaped body.
 5. Apparatus according to claim 1, wherein the shapedbody is releasably secured to a storage container.
 6. Apparatusaccording to claim 5, wherein the shaped body forms a bottom portion ofthe storage container.
 7. Apparatus according to claim 5, wherein theshaped body is secured to the storage container by a screw connection.8. Apparatus according to claim 5, wherein the shaped body is in theform of an insert in the storage container.
 9. Apparatus according toclaim 8, wherein the insert has bores arranged at a predeterminedspacing from a bottom of the container.
 10. Apparatus according to claim9, wherein the bores are provided in an insert portion which extendssubstantially parallel to the container bottom.
 11. Apparatus accordingto claim 11, wherein the platinum layer is arranged in an aqueouscontact lens care agent.
 12. Apparatus according to claim 11, whereinthe contact lens care agent is a 3% H₂O₂ solution for disinfectingcontact lenses.